Oil reserves are sometimes discovered in Bangladesh and this creates hope among the people as well as in the media. Administrative officials deliver inspiring statements and they also express good feelings. The officials also try to take credit for the discovery. Some of them go to the oil reserve and laud the mining experts. But no further effective development plan is seen to be taken over the matter.
After a few days, nobody talks about the discovery of oil. Steps are not seen to be taken for the overall development of the oil reserve by forming a team comprising geologists and technical experts who are directly involved in such a type of discovery.
Exploration activity from a well of discovered oil reserve is limited to the years till oil comes out naturally. Following production of a small amount of the total reserve from that well in this way, the well is shut within a few years. A big portion of the reserve remains under the earth, providing an instance of immature and weak management.
As the scientific method for the development of oil fields is not followed, the oil well gets shut. This is what happened with the Haripur oil field, which was earlier discovered in Bangladesh. The question is, whether this will be repeated in the case of this newly discovered oil reserve.
Why was the Haripur oil field not developed?
First oil reserve was discovered in Bangladesh in 1986. With much enthusiasm across the country, the production started in 1987. Oil production started from the well named Sylhet-7. Oil naturally comes up from the well. Although 300-400 barrels of oil were extracted every day at the initial stage, the pressure of oil continues to decrease. Under such a circumstance, mechanical management was not applied to increase pressure of the layer of oil. Moreover, new wells were also not brought under the production. As a result, the well was shut after it naturally produced oil for seven years.
Later no development plan was taken over the Haripur oil field. According to a primary survey, the Haripur oil field has a reserve of at least 10 million barrels of oil. A total of 500,000 barrels were produced from this oil field between 1987 and 1994. Only five per cent of the total reserve was extracted. Ninety five per cent remains under the earth.
What is the traditional method of developing oil fields?
The oil naturally comes up from the oil field that is discovered in the well. Oil remains under pressure when it stays underground. This pressure helps oil come up. With the passage of time, the production of oil decreases due to the decrease in pressure. Within a short period, the well is shut. During this period, the traditional method is to use an artificial lifting machine for the production of oil. In this case, installation of a big rod pump is a natural system which is technically cost-effective and this can be managed easily.
The production of oil increases due to using a rod pump as this enhances the pressure. Such types of digging and production in more than one well take place in the oil field. Later, oil cannot be extracted at one stage despite use of a pump. This stage of oil production is called primary recovery.
At the end of the primary recovery stage, oil production starts at the secondary recovery stage. For carrying out secondary recovery, new wells adjacent to the oil field are dug for pushing water under the earth. These wells are called injection wells. If water is pushed through these wells, it goes to the oil layer and creates pressure. As a result, oil production starts again. Oil can be produced for a long time through this method and this is followed in all oil producing countries in the world.
What should be done with the new well?
Aforementioned discussion has explained the traditional ways of development of an oil field. It also explained how deviation from that traditional method led to the failure of Haripur oil well due to immature and incomplete management. We have to learn from these mistakes.
The production and development of the new oil field should be in line with the traditional and well established technical system. For that, rod pumps and artificial lift should be used in oil wells for extraction on time.
Traditional methods have to be used at primary recovery and secondary recovery stages. Otherwise, depending solely on the own energy-based production system of a well like in Haripur oil well will become a failure.
Horizon of possibilities
In Bangladesh, natural gas has been discovered for a long time. Natural gas and mineral oil originate and reside in the same environment underground. That’s why the gas-rich countries are also found to be oil-rich. So the discovery of oil alongside natural gas is a positive sign for Bangladesh.
Geologists say that the Sylhet area has more oil reservoirs and further exploration will help find them. The efficiency of Bangladeshi geologists in exploring oil and gas is well established. As in the Haripur oil field, local experts were behind the discovery of the recently found oil field in Sylhet. Although the drilling contractor here was China’s Sinopec, the drilling was supervised and instructed by geologists of Sylhet Gas Fields Limited (FGFCL). The local geologists are credited for bringing the oil layer in control after the well met a blowout accident due to high pressure. Sinopec officials also acknowledged this.
The daily production rate of oil in the current or previously discovered fields in Bangladesh is small and will not meet any significant portion of the country’s demand. However, the correct and traditional way of the management of the oil fields and intensified oil exploration will bring some positive results. It is rational to expect discovery of enough oil in a country where enough gas has been discovered. Now the country needs to engage in more exploration activities and follow an efficient system of developing the discovered oil fields.
* Badrul Imam is the honorary professor of the department of geology, Dhaka University